Method for producing a fibre-composite made from amorphous, chemically modified polymers with reinforcement fibres

ABSTRACT

The invention relates to a method for producing a thermoplastic fibre composite containing a thermoplastic moulding compound (A) as a polymer-matrix (M), reinforcement fibres (B), and optionally additive (C). Said method comprises the following steps: i) flat structures (F) made from reinforcing fibres (B) treated with a silane sizing material are provided, ii) the flat structures (F) are placed in a thermoplastic molding compound (A) which comprises at least 0.3 mol %, with respect to components (A), of a chemically reactive functionality, iii) chemically reactive groups of the thermoplastic molding compound (A) are reacted in the polymer matrix (M) with the polar groups of the treated reinforcing fibres (B), iv) the at least one additive (C) is optionally incorporated v) cooling. Said method is particularly suitable for producing fibrous composites.

The present invention relates to a process for producing fiber compositematerials (also called organosheets) comprising a thermoplastic moldingcompound A and at least one ply of reinforcing fibers B, wherein the atleast one ply of the reinforcing fibers B is embedded into the matrixwith the thermoplastic molding compound A and wherein the thermoplasticmolding compound A has at least one chemically reactive functionality,the surface of reinforcing fiber B has been treated with a silane sizeand the concentration of functional groups (chemically reactivefunctionalities) has at least 0.3 mol %.

Fiber composite materials or organosheets usually consist of a multitudeof reinforcing fibers embedded into a polymer matrix. The fields of useof fiber composite materials are manifold. For example, fiber compositematerials are used in the automotive and aerospace sector. In this case,fiber composite materials are intended to prevent the breakup or otherfragmentations of the matrix, in order thus to reduce the risk ofaccident resulting from distributed component shreds. Many fibercomposite materials are capable of absorbing comparatively high forcesunder stress before failing totally. At the same time, fiber compositematerials feature high strength and stiffness coupled with low densitycompared to conventional unreinforced materials, and furtheradvantageous properties, for example good aging and corrosionresistance.

The strength and stiffness of the fiber composite materials areadaptable here with respect to the direction of stress and type ofstress. It is the fibers here that are primarily responsible for thestrength and stiffness of the fiber composite material. Moreover, thearrangement thereof also determines the mechanical properties of therespective fiber composite material. The matrix, by contrast, servesprimarily for introduction of the forces to be absorbed into theindividual fibers and for retention of the three-dimensional arrangementof the fibers in the desired orientation. Since both the fibers and thematrix materials are variable, there are numerous possible combinationsof fibers and matrix materials.

In the production of fiber composite materials, the bonding of fibersand polymer matrix to one another plays an essential role.

The strength of the embedding of the fibers into the polymer matrix(fiber-matrix adhesion) can also have a considerable influence on theproperties of the fiber composite material.

For optimization of the fiber-matrix adhesion and in order to compensatefor “low chemical similarity” between the fiber surfaces and thesurrounding polymer matrix, reinforcing fibers are regularly pretreated.For this purpose, adhesion promoters are regularly added to what iscalled the size. A size (sizing agent) of this kind is regularly appliedto the fiber during the production in order to improve the furtherprocessibility of the fibers (such as weaving, laying, sewing). If thesize is unwanted for the later further processing, it first has to beremoved in an additional process step, for instance by burning it down.In some cases, glass fibers are also used in unsized form.

Then, for the production of the fiber composite material, a furtheradhesion promoter is applied in an additional process step. Size and/oradhesion promoter form a layer on the surface of the fibers, which canessentially determine the interaction of the fibers with theenvironment. Nowadays there is a multitude of different adhesionpromoters available. The person skilled in the art can choose a suitableadhesion promoter compatible with the matrix and with the fiberaccording to the field of use, the matrix to be used and the fibers tobe used.

One technical challenge is that, in the event of occurrence of totalfailure, the fiber composite material can undergo brittle fracture.Consequently, for example, there can be a considerable risk of accidentfrom torn components in the construction of components exposed to a highlevel of stress.

It is therefore desirable to provide fiber composite materials with awide range of stress under which total failure is improbable. What aredesirable at the same time are additionally good optical properties,such as the option of being able to produce various elements with smoothsurfaces by means of the fiber composite materials.

WO 2008/058971 described molding compounds that use groups ofreinforcing fibers. Each of the groups of reinforcing fibers is providedwith different adhesion promoter components that bring about thedifferent fiber-matrix adhesions. The second fiber-matrix adhesion islower than the first fiber-matrix adhesion, and the near-surface pliesof reinforcing fibers composed of reinforcing fibers from the firstgroup are formed with greater fiber-matrix adhesion. Matrix materialsproposed are thermosets such as polyesters and the thermoplasticspolyamide and polypropylene.

WO 2008/119678 describes a glass fiber-reinforced styrene acrylonitrilecopolymer (SAN), the mechanical properties of which are improved throughuse of maleic anhydride group-containing styrene copolymer and choppedglass fibers. The use of short fibers is therefore taught. However, nopointer is given to fiber composite materials.

CN 102924857 describes mixtures of styrene-maleic anhydride copolymerswhich are mixed with chopped glass and then have relatively highstrengths. However, the stress cracking resistance of such a materialwith respect to solvents is too low. The strength with respect to glassfiber composites is also much too low.

CN 101555341 describes mixtures of acrylonitrile-butadiene-styrene(ABS), glass fibers, maleic anhydride-containing polymers and epoxyresins. In the production, ABS and the maleic anhydride-containingpolymer are initially charged, in order first to add the epoxy resin andthen the glass fibers. The flowability of such a mixture comprising a(thermoset) epoxy resin is very limited.

KR 100376049 teaches mixtures of SAN, maleic anhydride- andN-phenylmaleimide-containing copolymer, chopped glass fibers and anaminosilane-based coupling agent. The use of such a coupling agent leadsto additional processing steps and hence increases the production costs.

US 2011/0020572 describes organosheet components having a hybrid designcomposed, for example, of a highly free-flowing polycarbonate component.This involves rendering polycarbonate (PC) free-flowing by means ofsuitable additives, such as by means of hyperbranched polyesters,ethylene/(meth)acrylate copolymers or low molecular weight polyalkyleneglycol esters.

EP-A 2 251 377 describes organosheets based on individual fibers orfiber rovings.

(Glass) fibers in the prior art are frequently treated with a size whichprotects the fibers from one another in particular. Mutual damage viaabrasion is to be avoided. Mutual mechanical contact is not supposed toresult in cross-fragmentation (fracturing).

Moreover, by means of the size, the operation of cutting the fibers canbe facilitated, in order to obtain an equal stack length in particular.In addition, the size can prevent agglomeration of the fibers. Thedispersibility of short fibers in water can be improved. It is thuspossible to obtain homogeneous sheetlike structures by the wet layingmethod.

A size can contribute to establishment of improved cohesion between theglass fibers and the polymer matrix in which the glass fibers act asreinforcing fibers. This principle is employed particularly in the caseof the glass fiber-reinforced plastics (GFRP).

To date, the glass fiber sizes have generally comprised a large numberof constituents, for example film formers, lubricants, wetting agentsand adhesion promoters.

A film former protects the glass filaments from mutual friction and canadditionally enhance affinity for synthetic resins, in order thus topromote the strength and cohesion of a composite material. Mentionshould be made of starch derivatives, polymers and copolymer of vinylacetate and acrylic esters, epoxy resin emulsions, polyurethane resinsand polyamides with a proportion of 0.5% to 12% by weight, based on theoverall size.

A lubricant imparts suppleness to the glass fibers and their products,and reduces the mutual friction of the glass fibers, including theproduction. Often, however, the adhesion between glass and syntheticresin is impaired by the use of lubricants. Mention should be made offats, oils and polyalkyleneamines in an amount of 0.01% to 1% by weight,based on the overall size.

A wetting agent brings about lowering of the surface tension andimproved wetting of the filaments with the size. For aqueous sizes,mention should be made, for example, of polyfatty acid amides in anamount of 0.1% to 1.5% by weight, based on the overall size.

There is often no suitable affinity between the polymer matrix and theglass fibers. This gap can be bridged by adhesion promoters whichincrease the adhesion of polymers on the fiber surface. Mention shouldbe made of most organofunctional silanes, for exampleaminopropyltriethoxysilane, methacryloyloxypropyltrimethoxy-silane,glycidyloxypropyltrimethoxysilane and the like.

Silanes which are added to an aqueous size are usually hydrolyzed tosilanols. These silanols can then react with reactive (glass) fibersurfaces and hence form an adhesion promoter layer (with a thickness ofabout 3 nm).

Consequently, functional agents of low molecular weight having silanolgroups can react at the glass surface, in which case these agents of lowmolecular weight then react further (for example in epoxy resins) and inso doing assure chemical binding of the glass fiber to the polymermatrix. However, such production is time-consuming and takes betweenabout 30 minutes and more than one hour for complete curing of thepolymers (for example the abovementioned epoxy resins).

It therefore seems desirable, in an improved process, to combine alreadypolymerized melts with glass fibers or other reinforcing fibers.

Functionalization by reaction with polymers is likewise known. Forinstance, it is possible, through use of polycarbonate types of lowmolecular weight, to efficiently impregnate the glass fiber weave orscrim and to conduct “grafting” by reaction of functional groups on theglass fiber surface with the polycarbonate, which increasescompatibility with the polymer. However, this procedure has thedisadvantage that polycarbonate (PC) has a very high viscosity and it isnecessary for this impregnation step to use PC of low molecular weight,i.e. low viscosity, which is of extremely poor suitability for use, forexample has low resistance to agents that trigger stress cracking, suchas polar solvents.

One technical object of the invention is that of providing a process forproducing a fiber composite material (organosheet) having suitableproperties for production of molded bodies, films and coatings. Thefiber composite material should be based on a solid composite materialwhich is easy to process, is substantially inert with respect toconventional solvents, has good stress cracking resistance and has asmooth surface. Ideally, the fiber composite material does not need anyadhesion promoter. The invention likewise provides a fiber compositematerial which has been or is obtained from the process of theinvention.

It has been found that, surprisingly, a fiber composite materialcomprising at least one specific thermoplastic molding compound A asmatrix, at least one ply of pretreated reinforcing fibers B, andoptionally at least one additive C, gives a material which has goodstrength and is resistant to stress cracking and to solvents.

One aspect of the present invention relates to a process for producing athermoplastic fiber composite material comprising a thermoplasticmolding compound A as polymer matrix M, reinforcing fibers B, andoptionally at least one additive C, comprising the steps of:

-   i) providing sheetlike structures F composed of reinforcing fibers B    treated with a silane size,-   ii) introducing the sheetlike structures F into a thermoplastic    molding compound A having at least 0.3 mol %, based on component A,    of a chemically reactive functionality (in the form of functional    monomers),-   iii) reacting chemically reactive groups in the thermoplastic    molding compound A in the polymer matrix M with the polar groups at    the surface of the treated reinforcing fibers B,-   iv) optionally incorporating the at least one additive C and    consolidating the fiber composite material,-   v) cooling and optionally further process steps.

The invention provides a process for producing a thermoplastic fibercomposite material, wherein the fiber composite material is producedfrom:

-   a) 30% to 95% by weight, often 38% to 75% by weight, of the    thermoplastic molding compound A as polymer matrix,-   b) 5% to 70% by weight, often 24.9% to 61.9% by weight, of the    sheetlike structure F composed of reinforcing fibers B, and-   c) 0% to 40% by weight, often 0.1% to 25% by weight, of additive C.

The person skilled in the art will appreciate that the thermoplasticmolding compound A, in accordance with the invention, comprises at leastone (co)polymer having at least one chemically reactive functionalitythat reacts with chemical groups on the surface of the reinforcing fibercomponent B during the process for producing the fiber compositematerial. Such a (co)polymer comprises at least one functional monomerA-I, the functionality of which reacts with chemical groups on thesurface of the reinforcing component B during the process for producingthe fiber composite material. The (co)polymer comprising monomer A-I isalso referred to herein as polymer component (A-a).

Optionally, the thermoplastic molding compound A may also comprise oneor more (co)polymers that are optionally also free of any suchchemically reactive functionality (and therefore do not contain anyfunctional monomer A-I) and hence do not react with chemical groups atthe surface of the reinforcing fiber component B during the process forproducing the fiber composite material. Such a (co)polymer is alsoreferred to herein as polymer component (A-b).

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the fiber composite material isproduced from:

-   -   a) 30% to 70% by weight of a thermoplastic molding compound A,    -   b) 29% to 69% by weight of the sheetlike composite F composed of        reinforcing fibers B, and    -   c) 1% to 20% by weight of additive C.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the thermoplastic molding compound Aused as matrix M is amorphous.

The process can be used for production of a (partly) translucent and/orprintable fiber composite material.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the thermoplastic molding compound Aused as polymer matrix M is amorphous and is selected from a group ofcopolymers modified by a chemically reactive functionality that arebased on:

styrene-acrylonitrile copolymers, alpha-methylstyrene-acrylonitrilecopolymers, impact modified acrylonitrile-styrene copolymers, especiallyacrylonitrile-butadiene-styrene copolymers (ABS) andacrylonitrile-styrene-acrylic ester copolymers (ASA), and blends of thecopolymers mentioned with polycarbonate or polyamide.

It will be appreciated that, in accordance with the invention, at leastone of the (co)polymer components of the thermoplastic molding compoundA is a (co)polymer having at least one chemically reactive functionalityas described herein (polymer component (A-a)). Each of the copolymercomponents mentioned in the preceding paragraph may accordingly alsohave, in addition to the monomers mentioned explicitly, a reactivefunctionality which can react with the surface of the fibers B duringthe production of the fiber composite material. It is thus possible foreach of the aforementioned (co)polymers also to be a polymer component(A-a).

Accordingly, the aforementioned polymer components, in their use aspolymer component (A-a), will generally also comprise at least onemonomer A-I that imparts the chemically reactive functionality (andtherefore the reaction with fibers B). In that case, these can also bereferred to as, for example: polystyrene (A-I) copolymer,styrene-acrylonitrile (A-I) copolymer, α-methylstyrene acrylonitrile(A-I) copolymer, impact-modified acrylonitrile-styrene (A-I) copolymer,especially acrylonitrile-butadiene-styrene (A-I) copolymer (ABS-(A-I))and acrylonitrile-styrene-acrylic ester (A-I) copolymer (ASA-(A-I)).Blends of the copolymers mentioned with polycarbonate or polyamide arealso possible.

It is optionally possible for the aforementioned polymer components, intheir use as polymer component (A-a), to also additionally comprise asecond monomer (or even a third monomer) that imparts the chemicallyreactive functionality.

By way of example, therefore, the aforementioned polymer components (intheir use as polymer component (A-a)), in the case of use of maleicanhydride (MA) as monomer A-I, can also be referred to as, for example:polystyrene-maleic anhydride copolymer, styrene acrylonitrile-maleicanhydride copolymer, α-methylstyrene-acrylonitrile-maleic anhydridecopolymer, impact-modified acrylonitrile-maleic anhydride copolymer,especially acrylonitrile-butadiene-styrene-maleic anhydride copolymer(ABS-MA) and acrylonitrile-styrene-acrylic ester-maleic anhydridecopolymer (ASA-MA). Blends of the copolymers mentioned withpolycarbonate or polyamide are also possible. It will be appreciatedthat the same also applies to other monomers A-I.

It is optionally possible to use any one or more other (co)polymershaving no such functionality (as polymer component (A-b)) in addition tothe one or more polymer component(s) (A-a). Here too, it is possible, byway of example, to use the aforementioned (co)polymers (and sopolystyrene, styrene-acrylonitrile copolymers,α-methylstyrene-acrylonitrile copolymers, impact-modifiedacrylonitrile-styrene copolymers, especiallyacrylonitrile-butadiene-styrene copolymers (ABS) andacrylonitrile-styrene-acrylic ester copolymers (ASA), and also blends ofthe copolymers mentioned with polycarbonate or polyamide), but in thatcase, without the functionality (and so without reactive monomer A-I).

More preferably, polymer component (A-a) of the thermoplastic moldingcompound A is based on a SAN copolymer.

It will be apparent to the person skilled in the art that the SANcopolymer in that case additionally comprises a monomer A-I that reactswith the surface of the fibers B during the production process.Accordingly, the SAN copolymer in its use as polymer component (A-a) mayalso be an SAN-(M-I) copolymer (=SAN-(M-I) terpolymer), by way ofexample an SAN-MA copolymer (=SAN-MA terpolymer).

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the thermoplastic molding compound Aused as polymer matrix M is polystyrene (glass-clear “PS” orimpact-resistant, for example “HIPS”).

The feature “modified by a chemically reactive functionality” means herethat the copolymer also comprises those monomers (as a component) thatlead to reactive chemical groups in the copolymer, for example viaincorporation of maleic anhydride monomers into the polymer chain.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the thermoplastic molding compound Aconsists of styrene-acrylonitrile copolymers and/oralpha-methylstyrene-acrylonitrile copolymers that have been modified bya chemically reactive functionality, especially maleic anhydride (MA).

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the chemically reactive functionalityof the thermoplastic molding compound A is based on components selectedfrom the group consisting of maleic anhydride, N-phenylmaleimidetert-butyl (meth)acrylate and glycidyl (meth)acrylate, preferablyselected from the group consisting of: maleic anhydride,N-phenylmaleimide and glycidyl (meth)acrylate.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the surface of the reinforcing fibersB comprises one or more of the functions from the group of hydroxyl,ester and amino groups.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein molding composition A is produced byusing 0.5% to 5% by weight of monomers A-I, based on component A, havinga chemically reactive functionality.

Preferably, the fibers B take the form of sheetlike structures F(weaves, mats, nonwovens, scrims or knits) and/or of continuous fibers(including fibers that are the product of single fiber twisting).

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the sheetlike structure F is a woven,a scrim, a mat, a nonwoven or a knit.

The fibers B are therefore preferably not short fibers (“choppedfibers”) and the fiber composite material is preferably not a shortglass fiber-reinforced material. At least 50% of the fibers B preferablyhave a length of at least 5 mm, more preferably at least 10 mm or morethan 100 mm. The length of the fibers B also depends on the size of themolding T which is produced from the fiber composite material.

In a preferred embodiment, the fibers B are embedded into the fibercomposite material in layers, preferably embedded into the fibercomposite material in the form of a woven or scrim, especially in theform of a woven.

The person skilled in the art will be aware that wovens, mats,nonwovens, scrims or knits differ from short fibers since, in the formercase, larger contiguous sheetlike structures F that will generally belonger than 5 mm are formed. The person skilled in the art will be awarethat the sheetlike structures F here are preferably present in such aform that they (largely) permeate the fiber composite material.Therefore, the sheetlike structures F are preferably in such a form thatthey (largely) permeate the fiber composite material. “Largely permeate”means here that the sheetlike structure F or endless fibers permeatemore than 50%, preferably at least 70% and especially at least 90% ofthe length of the fiber composite material. The length of the fibercomposite material here is the greatest extent in any of the threespatial directions. With greater preference, the sheetlike composites For continuous fibers permeate more than 50%, preferably at least 70% andespecially at least 90% of the area of the fiber composite material. Thearea here is the area of the greatest extent in two of the three spatialdirections. The fiber composite material is preferably (largely)two-dimensional.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein component A is produced from 65% to80% by weight of (α-methyl)styrene, 19.7% to 32% by weight ofacrylonitrile and 0.3% to 3% by weight of maleic anhydride, and whereinthe sheetlike structure F is a woven, a scrim, a mat, a nonwoven or aknit.

More preferably, the maleic anhydride content in component A is 0.2% to2% by weight, even more preferably 0.33% to (about) 1% by weight,especially (about) 1% by weight (and so 0.5% to 1.49% by weight), asapparent from the experimental examples.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the reinforcing fibers B consist ofglass fibers comprising silane groups at the surface as chemicallyreactive functionality.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the reinforcing fibers B consist ofglass fibers comprising silanol groups at the surface as chemicallyreactive functionality.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the fiber composite material has aribbed structure or a sandwich structure. The process steps for forminga ribbed structure are known to those skilled in the art, and one reasonfor doing so is in order to avoid problems that arise from high wallthicknesses in moldings. The ribbed structure offers a suitable means ofincreasing stiffness with simultaneous reduction in the wall thickness.The reason for the improvement in the component stiffness by a ribbedstructure is an increase in the moment of inertia. In general,improvement in the dimensions of ribs also includes production-relatedand construction factors.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the fiber composite material has alayered structure and comprises two or more layers.

By way of example, the further layers may be of the same or elsedifferent construction with respect to those described above. In apreferred embodiment, the invention relates to the use of athermoplastic fiber composite material as described above, wherein thefiber composite material has a layered structure and comprises more thantwo, often more than three, layers. By way of example, all the layersmay be the same and be in accordance with the invention, or some of thelayers may have a different construction than those of the invention.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the temperature in the production ofthe fiber composite material (especially in step (iii)) is at least 200°C., preferably at least 250° C. and more preferably at least 300° C.

The invention also provides a process for producing a thermoplasticfiber composite material, wherein the residence time in the productionof the fiber composite material at temperatures of at least 200° C. isnot more than 10 minutes, preferably not more than 5 minutes, morepreferably not more than 2 minutes and especially not more than 1minute. The thermal treatment often takes from 10 to 60 seconds.

The invention also relates to a fiber composite material produced asdescribed above. The invention also relates to the use of a fibercomposite material produced as described above for production of moldedbodies, films and coatings.

Component A

The fiber composite material comprises at least 20% by weight, generallyat least 30% by weight, based on the total weight of the fiber compositematerial, of the thermoplastic matrix M or the thermoplastic moldingcompound A.

The thermoplastic matrix M comprising the molding compound A is presentin the fiber composite material at preferably from 30% to 95% by weight,more preferably from 32% to 90% by weight, even more preferably from 35%to 80% by weight, often from 38% to 75% by weight and especially from38% to 70% by weight, based on the fiber composite material. Preferably,the thermoplastic matrix M corresponds to the thermoplastic moldingcompound A.

Preferably, the thermoplastic molding compound A consists mainly (to anextent of more than 50%) of polystyrene or a copolymer (A-1). In oneembodiment, the thermoplastic molding compound A consists to an extentof at least 75% by weight, preferably to an extent of at least 90% byweight, of the copolymer A-1. The thermoplastic molding compound A mayalso consist solely of copolymer A-1.

Any thermoplastics are useful as thermoplastic molding compound A for afiber composite material of the invention, but especially styrenecopolymers are used, especially SAN, SMMA (styrene-methyl methacrylatecopolymers), ABS and ASA, and also polystyrene (glass-clear=“PS”) orelse impact-resistant polystyrene (=high impact polystyrene, “HIPS”).

As already set out above, the person skilled in the art will appreciatethat, in accordance with the invention, at least one of the (co)polymercomponents of the thermoplastic molding compound A is a (co)polymerhaving at least one chemically reactive functionality as describedherein (polymer component (A-a)). It is preferable, accordingly, that atleast one of the aforementioned polymer components (and therefore atleast one (optionally modified) polystyrene and/or at least onecopolymer A-1 (styrene copolymer, especially SAN, SMMA, ABS and ASA))comprises at least one monomer A-I.

By way of example, in the case of use of maleic anhydride (MA) asmonomer A-I, the polystyrene may therefore be a polystyrene-maleicanhydride copolymer (S-MA); copolymer A-1 may, by way of example, bestyrene-acrylonitrile-maleic anhydride copolymer (SAN-MA),styrene-methyl methacrylate-maleic anhydride copolymer (SMMA-MA),acrylonitrile-butadiene-styrene-maleic anhydride copolymer (ABS-MA),acrylonitrile-styrene-acrylonitrile-maleic anhydride copolymer (ASA-MA).

Optionally, in addition to the at least one polymer component (A-a), itis possible to use any one or more further (co)polymers without any suchfunctionality (as polymer component (A-b)). It will be appreciated thatthis may optionally also be polystyrene, SAN, SMMA, ABS and/or ASA (ineach case not comprising any monomer A-I).

The thermoplastic molding compound A (component A) is preferably anamorphous molding compound, the amorphous state of the thermoplasticmolding compound (thermoplastic) meaning that the macromolecules arearranged entirely randomly without regular arrangement and orientation,i.e. without constant separation.

Preferably, the entire thermoplastic molding compound A has amorphousthermoplastic properties, and is therefore fusible and (substantially)noncrystalline.

As a result, the shrinkage of the thermoplastic molding compound A, andtherefore also of the entire fiber composite material, is comparativelylow. It is possible to obtain particularly smooth surfaces in themoldings.

As an alternative, component A comprises a semicrystalline component ofless than 60% by weight, preferably less than 50% by weight, morepreferably than 40% by weight, based on the total weight of component A.Semicrystalline thermoplastics form both chemically regular andgeometric regions, meaning that there are regions in which crystallitesform. Crystallites are parallel-bundled arrangements of sections ofmolecules or folds of chains of molecules. Individual chain moleculesmay partly traverse the crystalline or amorphous region. They cansometimes even belong to two or more crystallites at the same time.

The thermoplastic molding compound A may also be a blend of amorphousthermoplastic polymers and semicrystalline polymers.

The thermoplastic molding compound A may, for example, be a blend of a(optionally A-I-present) styrene copolymer (such as modified SAN) withone or more polycarbonate(s) and/or one or more semicrystalline polymers(such as polyamide), where the proportion of semicrystalline blendcomponents in the overall component A should be less than 50% by weight,preferably less than 40% by weight.

According to the invention, the thermoplastic molding compound A usedcomprises at least one copolymer A-1 comprising monomers A-I which enterinto covalent bonds with the functional groups B-I of the embeddedreinforcing fibers B. The proportion of monomers A-I in thethermoplastic molding compound A may be chosen in a variable manner. Thehigher the proportion of monomers A-I and of the functional groups(B-I), the stronger it is also possible for the bond to be between thethermoplastic molding compound A and the reinforcing fibers B. MonomersA-I may still be present as monomers in copolymer A-1 or may beintegrated into the copolymer A-1. Preferably, the monomers A-I areintegrated into the copolymer A-1.

In a preferred embodiment, the copolymer A is formed with a proportionof monomers A-I of at least 0.3% by weight, preferably of at least 0.5%by weight, for example from 0.5% to 5% by weight, especially of at least1% by weight, for example 1% to 3% by weight, based on copolymer A.

The concentration of functional groups (chemically reactivefunctionality) is at least 0.3 mol %, preferably at least 0.5 mol %,especially 1 mol %, for example 1 to 3 mol %, based on 100 mol % ofmonomers which are used for production of the thermoplastic moldingcompound A.

In a preferred embodiment, functional groups in the thermoplasticmolding compound A are selected from the group consisting of anhydride,ester, carboxyl, amide, imide, acrylate and glycidyl groups.

Useful monomers A-I which can enter into covalent bonds with thefunctional groups B-I of the fibers B include all monomers that haveproperties of this kind. Preferred monomers A-I here are those which canenter into covalent bonds through reaction with hydroxyl or aminogroups.

Preferably, the monomers A-I have:

-   (a) at least one functionality capable of entering into covalent    bonds with the functional groups B-I on the surface of the fibers B    (for instance by reaction with hydroxyl and/or amino groups); and-   (b) at least one second functionality capable of being incorporated    into the copolymer A-1, for example a double bond, preferably a    terminal double bond which is incorporated into the copolymer A-1 by    means of free-radical polymerization.

Optionally, the copolymer A-1 or else another (co)polymer present in thethermoplastic molding compound A may contain one or more furthermonomers capable of entering into covalent or noncovalent bonds with thefibers B.

In a preferred embodiment, the monomers A-I are selected from the groupconsisting of:

-   -   maleic anhydride (MA),    -   N-phenylmaleimide (PM),    -   tert-butyl (meth)acrylate and    -   glycidyl (meth)acrylate (GM).

In a more preferred embodiment, the monomers A-I are selected from thegroup consisting of maleic anhydride (MA), N-phenylmaleimide (PM) andglycidyl (meth)acrylate (GM).

It is also possible for two of these monomers A-I to be present in thecopolymer A-1.

The copolymer A-1 of the thermoplastic molding compound A may optionallyinclude further functional monomers A-II. Examples of copolymers A-1 arestyrene/maleic anhydride, styrene/acrylonitrile/maleic anhydride,styrene/glycidyl methacrylate, styrene/N-phenylmaleimide,styrene/acrylonitrile/N-phenylmaleimide, methylmethacrylate/N-phenylmaleimide, methyl methacrylate/maleic anhydride,methyl methacrylate/maleic anhydride/N-phenylmaleimide,acrylonitrile/styrene/tert-butyl (meth)acrylate,acrylonitrile/butadiene/styrene/tert-butyl (meth)acrylate,acrylonitrile/butyl acrylate/styrene/tert-butyl (meth)acrylate; examplesof copolymers A-1 are especially: styrene/maleic anhydride,styrene/acrylonitrile/maleic anhydride, styrene/glycidyl methacrylate,styrene/N-phenylmaleimide, styrene/acrylonitrile/N-phenylmaleimide,methyl methacrylate/N-phenylmaleimide, methyl methacrylate/maleicanhydride/N-phenylmaleimide.

The matrix component M comprises at least one thermoplastic moldingcompound A, especially one suitable for the production of fibercomposite materials. Preference is given to using amorphousthermoplastics for the molding compound A. For example, styrenecopolymers are used, such as styrene-acrylonitrile copolymers (SAN) orα-methylstyrene-acrylonitrile copolymers (AMSAN), impact-modifiedstyrene-acrylonitrile copolymers, such asacrylonitrile-butadiene-styrene copolymers (ABS), styrene-methylmethacrylate copolymers (SMMA), methacrylateacrylonitrile-butadiene-styrene copolymers (MABS) or acrylicester-styrene-acrylonitrile copolymers (ASA), the styrene copolymershaving been modified with monomers (A-I).

Blends of the aforementioned copolymers with polycarbonate orsemicrystalline polymers such as polyamide are also suitable, providedthat the proportion of semicrystalline blend components in component Ais less than 50% by weight. Very particular preference is given to usingABS copolymers (with modification by monomers A-I) as thermoplasticmolding compound A.

It will be appreciated that at least one of the polymer components inthe thermoplastic molding compound A has been modified here with monomerA-I (polymer component (A-a)); preferably, one or more of theaforementioned styrene copolymers has been modified with monomer A-I.Any other polymer components (for instance styrene copolymers,preferably those as specified above) that have optionally not beenmodified with monomer A-I (polymer component A-b)) may optionallyadditionally be present in the thermoplastic molding compound A.

Blends of the aforementioned copolymers (one or more polymer components(A-a) and optionally (A-b)) with polycarbonate or semicrystallinepolymers such as polyamide are also suitable, provided that theproportion of semicrystalline blend components in component A is lessthan 50% by weight. Very particular preference is given to usingSAN-(M-I) copolymers (with modification by monomers A-I) as aconstituent (optionally even as the sole polymeric constituent) of thethermoplastic molding compound A.

A modified (α-methyl)styrene-acrylonitrile copolymer used in accordancewith the invention as thermoplastic molding compound A is prepared from,based on the (α-methyl)styrene-acrylonitrile copolymer, 58% to 85% byweight, preferably 65% to 80% by weight, of (α-methyl)styrene, 14.7% to37% by weight, preferably 19.7% to 32% by weight, of acrylonitrile and0.3% to 5% by weight, preferably 0.3% to 3% by weight, of maleicanhydride.

More preferably, the maleic anhydride content in component A is 0.2% to2% by weight, even more preferably 0.33% to (about) 1% by weight,especially (about) 1% by weight (and so 0.5% to 1.49% by weight), asapparent from the experimental examples.

Mention should also be made of mixtures of styrene-acrylonitrilecopolymer with α-methylstyrene-acrylonitrile copolymer.

An acrylonitrile-butadiene-styrene copolymer of the invention asthermoplastic molding compound A is prepared by known methods fromstyrene, acrylonitrile, butadiene and a functional further monomer A-I,for example methyl methacrylate.

The modified ABS copolymer may contain, for example: up to 70% by weight(for instance 35% to 70% by weight) of butadiene, up to 99.9% by weight(for instance 20% to 50% by weight) of styrene and up to 38% by weight(for instance 9% to 38% by weight) of acrylonitrile, and also 0.1% to20% by weight, preferably 0.1% to 10%, more preferably 0.1% to 5%,especially 0.1% to 3% by weight, of a monomer A-I such as maleicanhydride. Component A can also be prepared from 3% up to 70% by weight(for instance 35% to 70% by weight) of at least one conjugated diene, upto 99.9% by weight (for instance 20% to 50% by weight) of at least onevinylaromatic monomer and up to 38% by weight (for instance 9% to 38% byweight) of acrylonitrile and 0.1% to 20% by weight, preferably 0.1% to10%, more preferably 0.1% to 5%, especially 0.1% to 3% by weight, of amonomer A-I such as maleic anhydride.

In a strongly preferred embodiment, the modified ABS copolymer (aspolymer component (A-a)) may comprise: 35% to 70% by weight ofbutadiene, 20% to 50% by weight of styrene and 9.7% to 38% by weight ofacrylonitrile, and also 0.3% to 5% by weight, preferably 0.3% to 3% byweight, of a monomer A-1, such as maleic anhydride. Component A can alsobe prepared from 35% to 70% by weight of at least one conjugated diene,20% to 50% by weight of at least one vinylaromatic monomer and 9.7% to38% by weight of acrylonitrile, and also 0.3% to 5% by weight,preferably 0.3% to 3% by weight, of a monomer A-I, such as maleicanhydride.

An (α-methyl)styrene-methyl methacrylate copolymer of the invention (aspolymer component (A-a)) as thermoplastic molding compound A is preparedfrom, based on the (α-methyl)styrene-methyl methacrylate copolymer, atleast 50% by weight, preferably 55% to 95% by weight, more preferably60% to 85% by weight, of (α-methyl)styrene, 4.9% to 45% by weight,preferably 14.9% to 40% by weight, of methyl methacrylate and 0.1% to 5%by weight, preferably 0.1% to 3% by weight, of a monomer A-I, such asmaleic anhydride. The (α-methyl)styrene-methyl methacrylate copolymermay be a random copolymer or may have a block polymer construction.Component A may also be prepared from, based on component A, at least50% by weight, preferably 55% to 95% by weight, more preferably 60% to85% by weight, of vinylaromatic monomer, 4.9% to 45% by weight,preferably 14.9% to 40% by weight, of methyl methacrylate and 0.1% to 5%by weight, preferably 0.1% to 3% by weight, of a monomer A-I, such asmaleic anhydride.

In a further preferred embodiment, component A of the invention is astyrene/butadiene copolymer (in each case optionally additionally amonomer M-I present), for example impact-resistant polystyrene, astyrene-butadiene block copolymer, for example Styrolux®, Styroflex®,K-Resin, Clearen, Asaprene, a polycarbonate, an amorphous polyester oran amorphous polyamide.

The person skilled in the art will appreciate that, in accordance withthe invention, at least one of the (co)polymer components of thethermoplastic molding compound A is a (co)polymer having at least onechemically reactive functionality as described herein (polymer component(A-a)). This may also be a polymer component as described abovecontaining at least one functional monomer A-I in said molding compound.It is optionally possible to use any one or more further (co)polymershaving no such functionality (as polymer component (A-b)).

In a further embodiment, the matrix M may consist of at least twodifferent thermoplastic molding compounds A. These different types ofmolding compound may have, for example, a different melt flow index(MFI), and/or different comonomers or additives.

According to the invention, the term “molecular weight” (Mw) can beunderstood in the broadest sense to mean the mass of a molecule or aregion of a molecule (for example a polymer strand, a block polymer or asmall molecule), which can be reported in g/mol (Da) and kg/mol (kDa).Preferably, the molecular weight (Mw) is the weight average, which canbe determined by means of the methods known in the prior art.

Preferably, the thermoplastic molding compounds A have a molecularweight Mw of 60 000 to 400 000 g/mol, more preferably of 80 000 to 350000 g/mol, where Mw can be determined by light scattering intetrahydrofuran (GPC with UV detector). The molecular weight Mw of thethermoplastic molding compounds A can vary within a range of +/−20%.

Preferably, the thermoplastic molding compound A comprises a styrenecopolymer modified by a chemically reactive functionality, which, apartfrom the addition of the monomers A-I, is formed essentially from thesame monomers as the “normal styrene copolymer”, where the monomercontent deviates by +/−5%, the molecular weight by +/−20% and the meltflow index (determined at a temperature of 220° C. and a load of kg byISO Method 1133) by +/−20%. ISO Method 1133 is preferably understood tomean DIN EN ISO 1133-1:2012-03.

In a preferred embodiment, the melt volume rate (MVR) of thethermoplastic polymer composition A used as polymer matrix is 10 to 70cm³/10 min, preferably 12 to 70 cm³/10 min, especially 15 to 55 cm³/10min at 220° C./10 kg (measured according to ISO1133).

In a particularly preferred embodiment, the melt volume rate (MVR) ofthe thermoplastic polymer composition A used as polymer matrix is 10 to35 cm³/10 min, preferably 12 to 30 cm³/10 min, especially 15 to 25cm³/10 min at 220° C./10 kg (measured according to ISO1133).

Alternatively, the melt volume rate (MVR) of the thermoplastic polymercomposition A used as polymer matrix may be 35 to 70 cm³/10 min,preferably 40 to 60 cm³/10 min, especially 45 to 55 cm³/10 min at 220°C./10 kg (measured according to ISO1133).

Alternatively or additionally, the viscosity number (J=(η/η₀−1)·1/c) ofthe thermoplastic polymer composition A used as polymer matrix,determined by means of a capillary viscometer and measured at roomtemperature (20° C.) for pellets dissolved in dimethylformamide, may be50 to 100 mL/g, preferably 55 to 85 mL/g. In a preferred embodiment, theviscosity number is 55 to 75 mL/g, preferably 60 to 70 mL/g, especially61 to 67 mL/g. In an alternative preferred embodiment, the viscositynumber is 60 to 90 mL/g, preferably 65 to 85 mL/g, especially 75 to 85mL/g.

Suitable preparation processes for component A are emulsion, solution,bulk or suspension polymerization, preference being given to solutionpolymerization (see GB 1472195).

In a preferred embodiment of the invention, component A is isolatedafter the preparation by methods known to those skilled in the art andpreferably processed to pellets. This may be followed by the productionof the fiber composite materials.

Component B

The fiber composite material (organosheet) contains at least 5% byweight, based on the fiber composite material, of the reinforcing fiberB (component B). The reinforcing fiber B is present in the fibercomposite material at from 5% to 70% by weight, more preferably fromoften 10% to 68% by weight, even more preferably from 20% to 65% byweight, often from 24.9% to 61.9% by weight and especially from 29% to61% by weight, based on the fiber composite material.

The reinforcing fiber B is used as sheetlike structure F. Thereinforcing fibers B may be any fiber having a surface which hasfunctional groups B-I that can enter into a covalent bond with themonomers A-I of component A.

According to the invention, the surface of reinforcing fiber B has beentreated with a silane size. This size serves, for example, as lubricantin weaving and could be chemically removed after weaving.

In a more preferred embodiment, the reinforcing fibers B are glassfibers having hydroxyl groups at the surface in the form of silanolgroups as chemically reactive functionality B-I.

In addition, the surface of the reinforcing fibers B may have furtherfunctional groups B-II such as hydroxyl, ester or amino groups.

The reinforcing fibers B may be embedded in the fiber composite materialas sheetlike structure F in any orientation and arrangement.

The reinforcing fibers B are present in the fiber composite material notin random homogeneous distribution, but as sheetlike structure, i.e. inplanes having a higher proportion and those having a lower proportion(and so as more or less separate plies). The starting point ispreferably a laminate-like or laminar construction of the fibercomposite material.

The sheetlike structure F of the reinforcing fibers B may take the form,for example, of weaves, mats, nonwovens, scrims or knits. Flat laminatesformed in this way contain composites of sheetlike reinforcing plies (ofreinforcing fibers B) built up layer by layer and plies of the polymermatrix that wets and coheres these, comprising at least onethermoplastic molding compound A. In a preferred embodiment, thereinforcing fibers B are embedded layer by layer in the fiber compositematerial. The reinforcing fibers B preferably take the form of asheetlike structure F.

In a scrim, the fibers are ideally in parallel and stretched form.Usually, endless fibers are used. Weaves form through the weaving ofendless fibers, for example of rovings. The weaving of fibers isnecessarily accompanied by undulation of the fibers. The undulationespecially brings about lowering of the fiber-parallel compressivestrength. Mats usually consist of short and long fibers loosely bondedby means of a binder. By virtue of the use of short and long fibers, themechanical properties of components made from mats are inferior to thoseof weaves. Nonwovens are structures formed from fibers of limitedlength, endless fibers (filaments) or cut yarns of any length and anyorigin that have been joined to form a nonwoven in some way and havebeen bonded to one another in some way. Knits are thread systemsresulting from mesh formation.

The sheetlike structure F is preferably a scrim, a weave, a mat, anonwoven or a knit. A particularly preferred sheetlike structure F is ascrim or a weave.

Component C

As a further component C, the fiber composite material used optionallycontains 0% to 40% by weight, preferably 0% to 30% by weight, morepreferably 0.1% to 25% by weight, often from 1% to 20% by weight, basedon the sum of components A to C, of one or more additives different fromcomponents A and B (auxiliaries and additives).

Mention should be made of particulate mineral fillers, processingauxiliaries, stabilizers, oxidation retardants, thermal decompositionstabilizers and ultraviolet decomposition stabilizers, lubricants anddemolding aids, flame retardants, dyes and pigments, and plasticizers.

Mention should also be made of esters as low molecular weight compounds.According to the present invention, it is also possible to use two ormore of these compounds. In general, the compounds are present with amolar mass of less than 3000 g/mol, preferably less than 150 g/mol.

Particulate mineral fillers may be provided, for example, by amorphoussilica, carbonates such as magnesium carbonate, calcium carbonate(chalk), powdered quartz, mica, a wide variety of different silicatessuch as alumina, muscovite, biotite, suzoite, tin maletite, talc,chlorite, phlogopite, feldspar, calcium silicates such as wollastoniteor kaolin, especially calcined kaolin.

UV stabilizers include, for example, various substituted resorcinols,salicylates, benzotriazoles and benzophenones, which can generally beused in amounts of up to 2% by weight.

According to the invention, oxidation retardants and thermal stabilizerscan be added to the thermoplastic molding compound. Sterically hinderedphenols, hydroquinones, substituted representatives of this group,secondary aromatic amines, optionally in conjunction with phosphorusacids or salts thereof, and mixtures of these compounds, are usablepreferably in concentrations of up to 1% by weight, based on the weightof the mixture.

In addition, it is possible according to the invention to add lubricantsand demolding agents which generally in amounts of up to 1% by weight ofthe thermoplastic composition. Mention should be made here of stearicacid, stearyl alcohol, alkyl stearates and stearamides, preferablyIrganox®, and esters of pentaerythritol with long-chain fatty acids. Itis possible to use the calcium, zinc, aluminum salts of stearic acid,and also dialkyl ketones, for example distearyl ketone. In addition, itis also possible to use ethylene oxide-propylene oxide copolymers aslubricants and demolding agents. In addition, it is possible to usenatural and synthetic waxes. These include PP waxes, PE waxes, PA waxes,grafted PO waxes, HDPE waxes, PTFE waxes, EBS waxes, montan wax,carnauba wax and beeswax.

Flame retardants may either be halogenated or halogen-free compounds.Suitable halogen compounds, where brominated compounds are preferableover the chlorinated compounds, remain stable in the course ofproduction and processing of the molding compound of the invention, suchthat no corrosive gases are released and the efficacy is not impairedthereby. Preference is given to using halogen-free compounds, forexample phosphorus compounds, especially phosphine oxides andderivatives of acids of phosphorus and salts of acids and acidderivatives of phosphorus. More preferably, phosphorus compounds containester, alkyl, cycloalkyl and/or aryl groups. Likewise suitable areoligomeric phosphorus compounds having a molecular weight of less than2000 g/mol as described, for example, in EP-A 0 363 608.

Pigments and dyes may also be present. These are generally present inamounts of 0% to 15%, preferably 0.1% to 10% and especially 0.5% to 8%by weight, based on the sum total of components A to C. The pigments forcoloring thermoplastics are common knowledge; see, for example, R.Gachter and H. Müller, Taschenbuch der Kunststoffadditive [Handbook ofPlastics Additives], Carl Hanser Verlag, 1983, p. 494 to 510. Mentionshould be made, as the first preferred group of pigments, of whitepigments such as zinc oxide, zinc sulfide, lead white (2 PbCO₃.Pb(OH)₂),lithopone, antimony white and titanium dioxide. Of the two most commoncrystal polymorphs (rutile and anatase type) of titanium dioxide, therutile form in particular is used for whitening of the molding compoundsof the invention.

Black color pigments that can be used in accordance with the inventionare iron oxide black (Fe₃O₄), spinel black (Cu(Cr,Fe)₂O₄), manganeseblack (mixture of manganese dioxide, silicon oxide and iron oxide),cobalt black and antimony black, and more preferably carbon black, whichis usually used in the form of furnace black or gas black (in thisregard see G. Benzing, Pigmente für Anstrichmittel [Pigments forPaints], Expert-Verlag (1988), p. 78ff). It is of course possible inaccordance with the invention to establish particular hues by usinginorganic chromatic pigments such as chromium oxide green or organicchromatic pigments such as azo pigments and phthalocyanines. Pigments ofthis kind are generally commercially available. It can also beadvantageous to use the pigments or dyes mentioned in a mixture, forexample carbon black with copper phthalocyanines, since color dispersionin the thermoplastics is generally facilitated.

Process for Producing the Fiber Composite Materials

Preferably, fiber composite materials (organosheets) are processed bythe injection molding or pressing method. It is thus possible togenerate a further cost advantage through integration of function, forexample the attachment of functional elements by injection molding orcompression, since it is possible to dispense with further assemblysteps, for example the attachment of functional elements by welding.

The process for producing a thermoplastic fiber composite materialcomprising a thermoplastic molding compound A as polymer matrix M,reinforcing fibers B, and optionally at least one additive C comprisesthe steps of:

-   i) providing sheetlike structures F composed of reinforcing fibers B    treated with a silane size,-   ii) introducing the sheetlike structures F into a thermoplastic    molding compound A having at least 0.3 mol %, based on component A,    of a chemically reactive functionality,-   iii) reacting chemically reactive groups in the thermoplastic    molding compound A in the polymer matrix M with the polar groups at    the surface of the treated reinforcing fibers B to form covalent    bonds,-   iv) optionally incorporating the at least one additive C and    consolidating the fiber composite material,-   v) cooling and optionally further process steps.

The production process may comprise the phases of impregnation,consolidation and solidification that are customary in the production ofcomposite materials, and the operation can be affected via the choice oftemperature, pressure and times allowed.

In a preferred embodiment, the fiber composite material comprises (orconsists of):

-   a) 30 to 95% by weight of at least one thermoplastic molding    compound A,-   b) 5% to 70% by weight of at least one reinforcing fiber B, and-   c) 0% to 40% by weight, often 0.1% to 25% by weight, of at least one    additive C.

The size is an impregnating liquid which is applied to the reinforcingfibers B, for example by spraying or dipping, prior to furtherprocessing, for example weaving. A sized fiber is more supple andresistant to mechanical stress. Without sizing, a warp thread can easilybecome brittle and ultimately break as a result of the constant frictionwith the weft thread.

In the production of glass fibers, for example, these are drawn from themelt at high speed. The thickness of the fibers is determined here bythe size of the dies and the takeoff speed. The hot fibers are cooleddown by spraying with water and wetted with size by means of an immersedroll, and individual filaments are then bundled to form rovings. Thesize has multiple functions. The rovings are bound by the size binderand hence gain adequate stability to abrasion in the course of transportand to tearing-out of individual fibers or fracture. Since the sizeusually comprises water as diluent, the rovings have to be dried. Forthis purpose, they are either wound up in wet form (to give what arecalled cakes) and then dried or processed in wet form and dried at alater stage. The glass fibers thus obtained can be incorporated intothermoplastics for reinforcement. In general, the proportion by weightof size in the dried glass fiber is between 0.1% and 10%.

The incorporation of the at least one sheetlike structure F into athermoplastic matrix M in step (ii) is preferably effected via meltingof the thermoplastic molding compound A and contacting thereof with atleast one sheetlike structure F composed of reinforcing fiber B fromstep (i).

Step (ii) of the process, the melting of the thermoplastic moldingcompound A and the contacting of this melt with the reinforcing fibersB, can be effected in any manner suitable for the purpose. In such animpregnation, the matrix M, consisting of at least one thermoplasticmolding compound A, can be converted to a free-flowing state and thereinforcing fibers B can be wetted to form an interface layer.

Steps (ii) and (iii) can also be conducted simultaneously. In that case,the contacting of the thermoplastic molding compound A with thereinforcing fibers B is followed immediately by a chemical reaction inwhich the monomers A-I form a covalent bond with the surface of thereinforcing fibers B (generally via a bond to the functional groupsB-I). This can, by way of example, be an esterification (e.g. theesterification of maleic anhydride monomers with silanol groups of aglass fiber). Alternatively, the formation of a covalent bond can alsobe initiated in a separate step (for example by an increase intemperature, free-radical initiators and/or photoinitiation). This canbe conducted at any suitable temperature.

Steps (ii) and/or (iii) are conducted at a temperature of at least 200°C., preferably at least 250° C., more preferably at least 300° C.,especially 300° C.-340° C.

It should preferably be ensured here that a minimum level of pyrolysisoccurs and the components used are not subject to thermal decomposition.

In a preferred embodiment, therefore, in the performance of steps (ii)and/or (iii), the residence time at temperatures of ≥200° C. is not morethan 10 min, preferably not more than 5 min, even more preferably notmore than 2 min, especially not more than 1 min. 10 to 60 seconds areoften sufficient for the thermal treatment.

The process, especially steps (ii) and (iii), can in principle beconducted at any pressure (preferably atmospheric pressure or elevatedpressure), with or without compression attachment of the components. Inthe case of compression attachment with elevated pressure, it ispossible to improve the properties of the fiber composite material.

In a preferred embodiment, therefore, steps (ii) and/or (iii) areconducted at a pressure of 5-100 bar with a pressing time of 10-60 s,preferably at a pressure of 10-30 bar with a pressing time of 15-40 s.

Preference is given to using styrene copolymers provided with at leastone chemically reactive functionality (A-I), i.e. amorphousthermoplastic matrices, as thermoplastic molding compound A. It is thuspossible to significantly increase the surface quality for theapplications which follow compared to the semicrystalline thermoplasticsfor lining parts of this kind, since the lower shrinkage of theamorphous thermoplastics significantly improves the surface topology, onaccount of the fiber-rich (crossing point in the case of weaves) andlow-fiber regions.

In step (iv), in the consolidation, air pockets in the fiber compositematerial are reduced and a good bond is established betweenthermoplastic molding compound A and reinforcing fibers B (especiallywhen they are layered embedded reinforcing fibers B). It is preferable,after impregnation and consolidation, to obtain a (very substantially)pore-free material composite. Additives may also optionally beincorporated in step (iv).

Alternatively, said steps can be executed in a separate sequence. Forexample, it is thus possible to prepare plies of reinforcing fibers Bwith differently prepared reinforcing fibers B, in which caseimpregnation of the reinforcing fibers B with the matrix ofthermoplastic molding compound A takes place. Thereafter, there may beimpregnated plies with reinforcing fibers B having differentfiber-matrix adhesion, which can be consolidated in a further operatingstep to give a material composite as fiber composite material.

Before the plies of reinforcing fibers B are laminated with the matrixof thermoplastic molding compound A, it is possible for at least some ofthe reinforcing fibers B to be subjected to a pretreatment, in thecourse of which the later fiber-matrix adhesion is influenced. Thepretreatment may, for example, be a coating step, an etching step, aheat treatment step or a mechanical surface treatment step. Moreparticularly, for example, it is possible to partly remove an adhesionpromoter that has already been applied by heating a portion of thereinforcing fibers B.

The reinforcing plies may be fully bonded to one another in theproduction process (lamination). Fiber composite material mats of thiskind offer optimized strength and stiffness in fiber direction and canbe processed further in a particularly advantageous manner.

The process may also comprise the production of a molding T.

In a preferred embodiment, the process comprises, as a further step (v),three-dimensional shaping to give a molding T.

This can be effected in any desired manner, for instance by mechanicalshaping by means of a shaping body, which may also be an embossedroller. Preference is given to shaping the still-formable fibercomposite material in which the thermoplastic molding compound A isstill (partly) in molten form. Alternatively or additionally, it is alsopossible for a cured fiber composite material to be shaped at lowtemperature.

Preferably, at the end of the process, a (largely) solid molding T isobtained.

Preferably, therefore, the process comprises, as a further step (v), thecuring of the molding T or the product obtained from step (iv). Thisstep can also be referred to as solidification. The solidification,which generally takes place with removal of heat, can subsequently leadto a ready-to-use molding T.

Optionally, the molding T can still be subjected to further processing(e.g. deburred, polished, colored etc.).

The process may proceed continuously, semicontinuously or batchwise.

In a preferred embodiment, the process is conducted as a continuousprocess, especially as a continuous process for producing smooth orthree-dimensionally embossed films.

Alternatively, it is also possible to produce moldings T in asemicontinuous or batchwise manner.

The organosheets have an amorphous thermoplastic matrix M. These can beattached with a ribbed structure by the injection molding method,laminated (welded) as outer layers onto a foamed thermoplastic core oronto a honeycomb core.

The reason for the improvement in the component stiffness via a ribbedstructure (formation of a ribbed structure) is the increase in the areamoment of inertia. In general, the optimal dimensioning of the ribstructure includes production-related, esthetic and constructionaspects.

In a particularly preferred embodiment, the present invention relates tothe process of the invention for producing a thermoplastic fibercomposite material, wherein component A is produced from

65% to 80% by weight of (α-methyl)styrene,19.9% to 32% by weight of acrylonitrile and0.1% to 3% by weight of maleic anhydride,wherein the sheetlike structure F is a scrim, a weave, a mat, a nonwovenor a knit, andwherein the residence time for production of the fiber compositematerial at temperatures of at least 200° C. is not more than 10minutes.

In a particularly preferred embodiment, the present invention relates toa process for producing a thermoplastic fiber composite materialcomprising

-   a) 30% to 95% by weight of the thermoplastic molding compound A as    polymer matrix, wherein component A is produced from 65% to 80% by    weight of (α-methyl)styrene, 19.7% to 32% by weight of acrylonitrile    and 0.3% to 3% by weight of maleic anhydride, and wherein the    sheetlike structure F is a woven, a scrim, a mat, a nonwoven or a    knit,-   b) 5% to 70% by weight of the sheetlike structure F composed of    reinforcing fibers B, wherein the surface of the reinforcing fibers    B comprises one or more of the functions from the group of hydroxyl,    ester and amino groups, and-   c) 0% to 40% by weight, often 0.1% to 25% by weight, of additive C,    comprising the steps of:-   i) providing sheetlike structures F composed of reinforcing fibers B    treated with a silane size,-   ii) introducing the sheetlike structures F into a thermoplastic    molding compound A having at least 0.3 mol %, based on component A,    of a chemically reactive functionality, at at least 200° C.,-   iii) reacting chemically reactive groups in the thermoplastic    molding compound A in the polymer matrix M with the polar groups at    the surface of the treated reinforcing fibers B, wherein the    residence time at temperatures of at least 200° C. is not more than    10 minutes,-   iv) optionally incorporating the at least one additive C and    consolidating the fiber composite material,-   v) cooling and optionally further process steps,    wherein the fiber composite material preferably has a ribbed    structure or a sandwich structure and/or the fiber composite    material has a layered structure and comprises more than two layers.

Even more preferably, the process has one or more further features asdescribed herein.

The reinforcing fibers B may be impregnated and consolidated as asheetlike structure F composed of reinforcing fibers B in a singleprocessing step with the matrix M comprising a thermoplastic moldingcompound A. The fiber composite material can be produced in aparticularly efficient manner in this way.

In a further embodiment, further groups of reinforcing fibers B arecoupled to the matrix M via further, different fiber-matrix adhesions.

If three or more groups of reinforcing fibers B with differentfiber-matrix adhesions are used, the behavior of the fiber compositematerial can be further influenced individually in a controlled andhighly individual manner. It is possible here to use different types offibers or identical types of fibers in each case.

It is likewise possible for warp and weft threads to consist ofdifferent reinforcing fibers and/or to differ in thickness. In addition,the warp and weft threads may have been treated with different size ordifferent concentrations of the size.

Groups of reinforcing fibers B may each be provided with differentadhesion promoter compositions that bring about the differentfiber-matrix adhesions. The different compositions may differexclusively in the concentrations or else have different compositions.What is essential is that the different adhesion promoter compositionsestablish significantly different fiber-matrix adhesions.

As early as in the production of the reinforcing fibers B, the adhesionpromoter may be applied as part of the size. However, it is alsopossible to provide an additional operation of thermal desizing or someother kind of desizing that destroys or removes the size alreadyapplied. Subsequently, it is then possible to coat the reinforcingfibers with a finish which comprises the adhesion promoter and ismatched to the respective matrix and the desired fiber-matrix adhesion.Alternatively, it is also possible to use polymer layers. For example,in the fiber composite material of the invention, it is possible to useadhesion promoters comprising crosslinkable polyetherurethane andpolyesterurethane polymers which act as film formers, together with anaminosilane adhesion promoter.

Preferably, finished reinforcing fibers (for example weaves) have beenfinished with modified silane sizes (for example Finish FK 800). Theyare very soft to the touch and barely fray at all on cutting.

The invention is described in detail in the examples, figures and claimswhich follow.

FIGURES

FIG. 1 shows the fiber composite materials W which have been obtainedaccording to experiment no. 1. FIG. 1A shows the visual documentation.FIG. 1B shows the microscope view of a section through the laminar fibercomposite material W arranged in horizontal alignment (on the left:25-fold magnification, on the right: 50-fold magnification), the fibersbeing clearly apparent as a horizontal dark-colored layer between thelight-colored layers of thermoplastic molding compound. FIG. 1C showsthe 200-fold magnification, it being apparent that the impregnation isincomplete at some points.

FIG. 2 shows the fiber composite materials W which have been obtainedaccording to experiment no. 2. FIG. 2A shows the visual documentation.FIG. 2B shows the microscope view of a section through the laminar fibercomposite material W arranged in horizontal alignment (on the left:25-fold magnification, on the right: 50-fold magnification), the fibersbeing clearly apparent as a horizontal dark-colored layer between thelight-colored layers of thermoplastic molding compound. FIG. 2C showsthe 200-fold magnification, it being apparent that the impregnation ispartially incomplete.

FIG. 3 shows the fiber composite materials W which have been obtainedaccording to experiment no. 3. FIG. 3A shows the visual documentation.FIG. 3B shows the microscope view of a section through the laminar fibercomposite material W arranged in horizontal alignment (on the left:25-fold magnification, on the right: 50-fold magnification), with noapparent layer of fibers. FIG. 3C shows the 200-fold magnification, itbeing apparent that the impregnation is substantially complete.

FIG. 4 shows the fiber composite materials W which have been obtainedaccording to experiment no. 4. FIG. 4A shows the visual documentation.FIG. 4B shows the microscope view of a section through the laminar fibercomposite material W arranged in horizontal alignment (on the left:25-fold magnification, on the right: 50-fold magnification), with noapparent layer of fibers. FIG. 4C shows the 200-fold magnification, itbeing apparent that the impregnation is incomplete at individual points.

FIG. 5 shows the fiber composite materials W which have been obtainedaccording to experiment no. 5. FIG. 5A shows the visual documentation.FIG. 5B shows the microscope view of a section through the laminar fibercomposite material W arranged in horizontal alignment (on the left:25-fold magnification, on the right: 50-fold magnification), with noapparent layer of fibers. FIG. 4C shows the 200-fold magnification, itbeing apparent that the impregnation is incomplete at a few points.

FIG. 6 shows the production of the fiber composite materials W (here:glass fiber weave) in the press intake V25-V28. It is clearly apparentthat a production process of this kind permits continuous production.Moreover, it is apparent via the embossment of the pattern that thefiber composite material W is also three-dimensionally formable.

FIG. 7 shows, in schematic form, the development of undesired formationof surface waves (texture).

EXAMPLES

The experiments which follow were conducted in an intermittent hot presscapable of producing a fiber/film composite from polymer film, melt orpowder, for quasi-continuous production of fiber-reinforcedthermoplastic semifinished products, laminates and sandwich sheets.

Sheet width: 660 mmLaminate thickness: 0.2 to 9.0 mmLaminate tolerances: max.±0.1 mm corresponding to semifinished productSandwich sheet thickness: max. 30 mmOutput: about 0.1-60 m/h, depending on quality and component thicknessNominal advance rate 5 m/hMold pressure: compression unit 5-25 bar, infinitely adjustable forminimum andmaximum mold size (optional)Mold temperature control: 3 heating zones and 2 cooling zonesMold temperature: up to 400° C.Mold length: 1000 mmPress opening distance: 0.5 to 200 mm

Technical Data of the Melt Plastification are:

Discontinuous melt discharge in center position for production offiber-reinforced thermoplastic semifinished products:Screw diameter: 35 mmMax. stroke volume: 192 cm³Max. screw speed: 350 rpmMax. discharge flow rate: 108 cm³/sMax. discharge pressure: 2406 bar (specific)

Flexural stress and flexural modulus were determined according to DIN14125:2011-05.

Components:

-   A1: styrene-acrylonitrile (S/AN) copolymer with the following    composition: 75% by weight styrene (S) and 25% by weight    acrylonitrile (AN), viscosity number 60, Mw 250 000 g/mol (measured    via gel permeation chromatography on standard columns with    monodisperse polystyrene calibration standards)-   A2: S/AN/maleic anhydride (MSA) copolymer with the composition (% by    weight): 74/25/1; concentration of functional groups: 1% by weight    of MA (98.1 g/mol) in 74% by weight of styrene (104.2 g/mol) and 25%    by weight of AN (53.1 g/mol), Mw 250 000 g/mol (measured via gel    permeation chromatography on standard columns with monodisperse    polystyrene calibration standards)-   A3: mixture of A2:A1=2:1, concentration of functional groups: 0.67%    by weight of MA-   A4: mixture of A2:A1=1:2, concentration of functional groups: 0.33%    by weight of MA-   B1: bidirectional glass fiber scrim 0/90° with basis weight=approx.    590 g/m²,    -   weft+warp=1200 tex (=1200 g/1000 m)[for example KN G 590.1 from        P-D Glasseiden GmbH]-   B2: glass fiber twill weave 2/2 with basis weight=approx. 576 g/m²,    weft+warp=1200 tex [for example GW 123-580K2 from P-D Glasseiden    GmbH]

The combinations and parameter settings for the process described inclaim 1 are listed in the following table:

TABLE 1 Compositions of comp. 1, comp. 2, comp. 10 and comp. 15 and ofthe inventive compositions V3 to V9 and V11 to V14. No. A1 A2 A3 A4 B1B2 T [° C.] t [s] Comp. 1 X X 260 20-30 Comp. 2 X X 300 30-30 V3 X X 28020-30 V4 X X 280 40 V5 X X 320 30-30 V6 X X 300 20-30 V7 X X 320 20-30V8 X X 310 20-30 V9 X X 320 20-30 Comp. 10 X X 320 20-30 V11 X X 32020-30 V12 X X 320 20-30 V13 X X 320 20-30 V14 X X 320 20-30 Comp. 15 X X320 20-30 X: proportion by weight of component A:B = 60:40

Table 1 shows the conditions in the experiments conducted.

In this context, the reactants and the temperature and pressing timewere varied. The pressure in all the test series was about 20 bar.

TABLE 2 Mean values for maximum flexural stress in warp and weftdirection for the organosheets produced according to the mixtures comp.2, V5, V7, V9, comp. 10, V12 to V14 and comp. 15, with a productiontemperature in each case of at least 300° C. Mean values for maximum No.Fiber direction flexural stress [MPa] Comp. 2 warp direction 211.23 weftdirection 184.94 V5 warp direction 670.48 weft direction 271.05 V7 warpdirection 590.98 weft direction 301.21 V9 warp direction 371.73 weftdirection 244.62 Comp. 10 warp direction 319.8 weft direction 236.01 V12warp direction 556.15 weft direction 484.24 V13 warp direction 528.96weft direction 386.83 V14 warp direction 513.95 weft direction 413.86comp. 15 warp direction 423.03 weft direction 301.40

The values shown in table 2 are the mean value of 9 measurements in eachcase. Table 2 shows that the inventive organosheets V5, V7, V9, V12, V13and V14 have a higher mean maximum flexural stress than the organosheetshaving a matrix comprising 75% by weight of styrene (S) and 25% byweight of acrylonitrile (AN) (comp. 10 and comp. 15). The comparison ofV9 with comp. 10 also shows that, under the same conditions (T=320° C.and t=30 s), the organosheet of the invention has greater flexuralstress both in warp direction and in weft direction.

It is found that the process for producing the fiber composite materialwith a thermoplastic molding compound A and reinforcing fibers B cangive improved products.

Further Examination of Multilayer Fiber Composite Materials TechnicalData of the Intermittent Hot Press (IVHP):

Quasi-continuous production of fiber-reinforced semifinished products,laminates and sandwich sheetsSheet width: 660 mmLaminate thickness: 0.2 to 9.0 mmLaminate tolerances: max.±0.1 mm corresponding to semifinished productSandwich sheet thickness: max. 30 mmOutput: about 0.1-60 m/h, depending on quality and component thicknessNominal advance rate 5 m/hMold pressure: press unit 5-25 bar, infinitely adjustable for minimumand maximum mold size (optional)Mold temperature control: 3 heating and 2 cooling zonesMold temperature: up to 400° C.Mold length: 1000 mmPress opening distance: 0.5 to 200 mmProduction direction: from right to left

Technical Data of the Melt Plastification:

Discontinuous melt discharge in center position for production offiber-reinforced thermoplastic semifinished products:Screw diameter: 35 mmMax. stroke volume: 192 cm³Max. screw speed: 350 rpmMax. discharge flow rate: 108 cm³/sMax. discharge pressure: 2406 bar (specific)

Here:

Melt volume: 22 ccmisobaric=pressure-controlled pressing operationisochoric=volume-control pressing operationT [° C.]=temperature of the temperature zones* (*the press has 3 heatingand 2 cooling zones, specified in production direction)p [bar]=pressure per cycle: isochoric 20s [mm]=distance limit for compression thickness: 1.1 mmTemperature profile: (i) 210 to 245° C., so about 220° C.

-   -   (ii) 300 to 325° C., so about 300° C.    -   (iii) 270 to 320° C., so about 280 to 320° C.    -   (iv) 160 to 180° C.    -   (v) 80° C.        t [sec]=pressing time per cycle: 20-30 s        Construction/lamination: 6-ply construction with middle melt        layer; production process: direct melt (SD)

Matrix Components A:

M1 (SAN type): styrene-acrylonitrile-maleic anhydride (SAN-MA)terpolymer (S/AN/MA: 74/25/1) with an MA content of 1% by weight and anMVR of 22 cm³/10 min at 220° C./10 kg (measured to ISO1133);M1b corresponds to the aforementioned component M1, with an additional2% by weight of industrial black mixed into the matrix.M2 (SAN type): styrene-acrylonitrile-maleic anhydride (SAN-MA)terpolymer (S/AN/MA: 73/25/2.1) with an MA content of 2.1% by weight andan MVR of 22 cm³/10 min at 220° C./10 kg (measured to ISO1133);M2b corresponds to the aforementioned component M2, with an additional2% by weight of industrial black mixed into the matrix.M3 (SAN type): blend of 33% by weight of M1 and 67% by weight of the SANcopolymer Luran VLN, so 0.33% by weight of maleic anhydride (MA) in theoverall blend;M3b corresponds to the aforementioned component M3, with an additional2% by weight of industrial black mixed into the matrix.PA6: semicrystalline, free-flowing polyamide Durethan B30SPD(OD): free-flowing amorphous optical grade polycarbonate for opticaldiscs;

Fiber Components B:

Glass filament twill weave (brief designations: GF-KG(LR) or LR), 2/2twill weave, basis weight 290 g/m², EC9 68 tex rovings, TF-970 finish,supply width 1000 mm (type: 01102 0800-1240; manufacture: Hexcel,obtained from: Lange+Ritter)Glass filament twill weave (brief designations: GF-KG(PD) or PD), 2/2twill weave, basis weight 320 g/m², 320 tex rovings, 350 finish, supplywidth 635 mm (type: EC14-320-350, manufacturer and supplier: PDGlasseide GmbH Oschatz)Glass filament scrim (brief designations: GF-GE(Sae) or Sae)0°/45°/90°/−45°, basis weight 313 g/m², 300 tex main rovings, PA sizefinish, supply width 655 mm (type: X-E-PA-313-655, no. 7004344,manufacturer and supplier: Saertex GmbH & Co. KG)Sae n.s.=300 g/m² glass filament scrim, manufacturer designation:Saertex new sizing, +45°/−45°/+45°/−45°Glass fiber nonwoven (brief designation: GV50), basis weight 50 g/m²,fiber diameter 10 μm, supply width 640 mm (type: Evalith S5030,manufacturer and supplier: Johns Manville Europe)

Visual Assessment

All the fiber composite materials produced were producible in each caseas flat organosheets (with a large area) in a continuous process, and itwas possible without any problem to cut these to size (in laminatable,customary transport dimensions, for instance 1 m×0.6 m). In the case ofthe transparent fiber composite materials, the embedded fiber materialwas just apparent on detailed backlit inspection. In the case of thefiber composite materials with a (black-)colored matrix, the embeddedfiber material was not/barely apparent even on closer backlit visualinspection.

Microscope Assessment

In this case, defects (craters, dips, etc.) were assessed viaepiluminescence microscopy, and the surface quality via confocal laserscanning microscopy (LSM). By means of LSM, a top view of athree-dimensional (3D) survey (7.2 mm×7.2 mm) of the local measurementregion and a two-dimensional (2D) representation of the differences inheight after scaling and use of various profile filters were created.Measurement errors and general distortion/skewness of the sample werecompensated for by the use of profile filters (noise filters and tiltfilters). The 2D high profile of the image was converted to lineprofiles via defined measurement lines by integrated software andevaluated with computer assistance.

Fiber composite materials each having four plies of the appropriatesheetlike structure of fibers (GF-KG(PD)(4) or Sae(4) here) embeddedinto the respective matrix were produced. In order to further increasethe comparability of the samples, a thin glass fiber nonwoven (GV50, seeabove) was applied to each side of the fiber composite materialsproduced. This had no noticeable effect on the mechanical properties.

The mean wave depth (MW Wt) and the median roughness (Ra) wereascertained for numerous fiber composite materials. It was found thatthe MW Wt for all fiber composite materials in which the matrixcomprises a functional component that can react with the fibers isdistinctly <10 μm, whereas in the case of fiber composite materials withcomparable PA6 and PD(OD) matrices it is distinctly <10 μm. The medianroughness values ascertained were also much less for fiber compositematerials of the invention. This is shown by way of example by themeasured values below.

TABLE 3 Test results of the LSM analysis with SAN matrix system - wavedepth (Wt) and median roughness (Ra) SAN(1) PC(1) PA6(1) Construction+GF-KG(PD)(4) Components M1b + PD M2 + PD M2b + PD M3b + PD PC(OD) + PDPA6 + PD MW Wt 7.141 7.187 5.181 5.425 11.745 12.323 MW Ra 3.995 4.4154.17 3.451 6.406 4.968

This likewise became clear when a scrim (such as Sae) was used in placeof the weave:

TABLE 4 Test results of the LSM analysis with SAN matrix system- wavedepth (Wt) and median roughness (Ra) Construction SAN(1) PA6(1)Construction +Sae(4) Components M1b + Sae M2b + Sae MW Wt 5.535 5.20517.05 MW Ra 4.261 4.24  4.861

In further tests, strength in warp direction and in weft direction wasexamined separately. It was shown that the fiber composite materials arevery stable both in warp direction and in weft direction. The fibercomposite materials are generally even more stable in warp directionthan in weft direction.

Mechanical Properties Matrix Components A

The matrix components A are as described above.

Fiber Components B (if not Described Above)

FG290=glass filament weave 290 g/m², manufacturer designation: HexcelHexForce® 01202 1000 TF970FG320=glass filament weave 320 g/m², manufacturer designation: PDGlasseide GmbH Oschatz EC14-320-350Sae=MuAx313, glass filament scrim 300 g/m², manufacturer designation:Saertex X-E-PA-313-655Sae n.s.=glass filament scrim 300 g/m², manufacturer designation:Saertex new sizing, +45°/−45°/+45°/−45°Number of layers (for example 4x=four layers of the respective fiberscrim or of the respective fibers)

The transparent fiber composite materials which follow were produced,into each of which was introduced flat fiber material. The fibercomposite materials produced each had a thickness of about 1.1 mm. Inorder to further increase the comparability of the samples, a thin glassfiber nonwoven (GV50, see above) was applied to each side of the fibercomposite materials produced. This has no noticeable effect on themechanical or optical properties. For the samples, the followingflexural strengths were ascertained according to DIN EN ISO 14125:

TABLE 5 Transparent fiber composite materials - flexural strength GlassModulus Con- content Thickness of Flexural No. struction [g/m²] Matrix[mm] elasticity strength F/T_1 4xFG290 1260 M2 1.09 18.41 658.89 F/T_24xFG320 1380 M2 1.09 18.17 634.32 F/T_3 4xSae 1352 M2 1.16 18.44 444.33F/T_4 Sae n.s. M2 1.17 15.93 621.04 F/T_5 4xFG320 1380 PC(OD) 1.14 23.36377.97

Additionally produced were the black-colored fiber composite materialswhich follow, in which 2% by weight of industrial black was mixed intothe matrix and into each of which flat fiber material was introduced.The fiber composite materials produced each had a thickness of about 1.1mm. In order to further increase the comparability of the samples, athin glass fiber nonwoven (GV50, see above) was applied to each side ofthe fiber composite materials produced. This has no noticeable effect onthe mechanical or optical properties. For the samples, the followingflexural strengths were ascertained according to DIN EN ISO 14125:

TABLE 6 Nontransparent fiber composite materials - flexural strengthGlass Modulus Con- content Thickness of Flexural No. struction [g/m²]Matrix [mm] elasticity strength F/S_1 4xFG290 1260 M2 1.07 21.61 661.73F/S_2 4xFG320 1380 M2 1.20 22.70 673.99 F/S_3 4xSae 1352 M2 1.15 14.92385.21 F/S_4 4xSae 1352 PA6 1.13 14.30 477.77 F/S_5 4xFG320 1380 PA61.11 16.95 471.97

In summary, it is found that the weaves used (FG290 and FG320) can beprocessed to give fiber composite materials having particularly highflexural strength. The fiber composite materials of the invention inwhich the matrix comprises a component that reacts with the fibers(here: maleic anhydride (MA)) have a significantly higher flexuralstrength than comparative molding compounds without any such component,for instance PC(OD) or PA6.

By comparison, for the noninventive Luran 378P G7 fiber compositematerial reinforced with short glass fibers, only a flexural strength of150 MPa was found, and so a much lower flexural strength.

In addition, for the fiber composite materials, the impact resistance orpenetration characteristics (dart test according to ISO 6603) wereascertained. Here too, the fiber composite materials showed a highstability of Fm>3000 N.

Optional Further Processing

It was also shown experimentally that the fiber composite materialsobtained had good formability to give three-dimensional semifinishedproducts, for example to give semifinished products in half-shell form.It was additionally shown that the fiber composite materials obtainedwere printable and laminatable.

Summary of the Experimental Results

The evaluation of different glass fiber-based textile systems withdifferent matrix systems to give a fiber composite material(organosheet) showed that good fiber composite materials (asorganosheets and semifinished products produced therefrom) can beproduced in a reproducible manner. These can be produced in colorless orcolored form. The fiber composite materials showed good to very goodoptical, tactile and mechanical properties (for instance with regard totheir flexural strength and puncture resistance). In mechanical terms,the weaves showed somewhat greater strength and stiffness than scrims.The styrene copolymer-based matrices (SAN matrices) tended to lead tobetter fiber composite materials in terms of the mechanical indices thanthe alternative matrices such as PC and PA6. The fiber compositematerials of the invention were producible in a semiautomatic or fullyautomatic manner by means of a continuous process. The fiber compositematerials (organosheets) of the invention have good formability to givethree-dimensional semifinished products.

1-16. (canceled)
 17. A process for producing a thermoplastic fibercomposite material comprising a thermoplastic molding compound A aspolymer matrix M, reinforcing fibers B, and optionally at least oneadditive C, comprising the steps of: i) providing sheetlike structures Fcomposed of reinforcing fibers B treated with a silane size, ii)introducing the sheetlike structures F into a thermoplastic moldingcompound A having at least 0.3 mol %, based on component A, of achemically reactive functionality, iii) reacting chemically reactivegroups in the thermoplastic molding compound A in the polymer matrix Mwith the polar groups at the surface of the treated reinforcing fibersB, iv) optionally incorporating the at least one additive C andconsolidating the fiber composite material, and v) cooling andoptionally further process steps.
 18. The process for producing athermoplastic fiber composite material as claimed in claim 17, whereinthe fiber composite material is produced from a) 30% to 95% by weight ofthe thermoplastic molding compound A as polymer matrix, b) 5% to 70% byweight of the sheetlike structure F composed of reinforcing fibers B,and c) 0% to 40% by weight, often 0.1% to 25% by weight, of additive C.19. The process for producing a thermoplastic fiber composite materialas claimed in claim 17, wherein the thermoplastic molding compound Aused as polymer matrix M is amorphous and is selected from the group ofcopolymers modified by a chemically reactive functionality that arebased on: styrene-acrylonitrile copolymers,alpha-methylstyrene-acrylonitrile copolymers, impact modifiedacrylonitrile-styrene copolymers, and blends of the copolymers mentionedwith polycarbonate or polyimide.
 20. The process for producing athermoplastic fiber composite material as claimed in claim 17, whereinthe thermoplastic molding compound A consists of copolymers selectedfrom the group consisting of styrene-acrylonitrile copolymers andalpha-methylstyrene acrylonitrile copolymers that have been modified bya chemically reactive functionality.
 21. The process for producing athermoplastic fiber composite material as claimed in claim 17, whereinthe chemically reactive functionality of the thermoplastic moldingcompound A is based on components selected from the group consisting of:maleic anhydride, N-phenylmaleimide, and glycidyl (meth)acrylate. 22.The process for producing a thermoplastic fiber composite material asclaimed in claim 17, wherein the surface of the reinforcing fibers Bcomprises one or more of the functions from the group of hydroxyl,ester, and amino groups.
 23. The process for producing a thermoplasticfiber composite material as claimed in claim 17, wherein moldingcompound A is produced using 0.5% to 5% by weight of monomers A-I, basedon component A, which have a chemically reactive functionality.
 24. Theprocess for producing a thermoplastic fiber composite material asclaimed in claim 17, wherein component A is prepared from 65% to 80% byweight of (α-methyl)styrene, 19.7% to 32% by weight of acrylonitrile,and 0.3% to 3% by weight of maleic anhydride, and wherein the sheetlikestructure F is a scrim, a weave, a mat, a nonwoven, or a knit.
 25. Theprocess for producing a thermoplastic fiber composite material asclaimed in claim 17, wherein the reinforcing fibers B consist of glassfibers comprising silanol groups on the surface as chemically reactivefunctionality.
 26. The process for producing a thermoplastic fibercomposite material as claimed in claim 17, wherein the fiber compositematerial has a ribbed structure or a sandwich structure.
 27. The processfor producing a thermoplastic fiber composite material as claimed inclaim 17, wherein the fiber composite material has a layered structureand comprises more than two layers.
 28. The process for producing athermoplastic fiber composite material as claimed in claim 17, whereinthe temperature in the production of the fiber composite material is atleast 200° C.
 29. The process for producing a thermoplastic fibercomposite material as claimed in claim 17, wherein the residence time inthe production of the fiber composite material at temperatures of atleast 200° C. is not more than 10 minutes.
 30. The process for producinga thermoplastic fiber composite material as claimed in claim 17, whereincomponent A is produced from 65% to 80% by weight of (α-methyl)styrene,19.9% to 32% by weight of acrylonitrile, and 0.1% to 3% by weight ofmaleic anhydride, wherein the sheetlike structure F is a scrim, a weave,a mat, a nonwoven, or a knit, and wherein the residence time forproduction of the fiber composite material at temperatures of at least200° C. is not more than 10 minutes.
 31. A fiber composite materialproduced as claimed in claim
 17. 32. A molding, film, or coatingcomprising the fiber composite material as claimed in claim
 31. 33. Theprocess for producing a thermoplastic fiber composite material asclaimed in claim 17, wherein the thermoplastic molding compound A usedas polymer matrix M is amorphous and is selected from the group ofcopolymers modified by a chemically reactive functionality that arebased on: impact modified acrylonitrile-styrene copolymers selected fromacrylonitrile-butadiene-styrene copolymers andacrylonitrile-styrene-acrylic ester copolymers.
 34. The process forproducing a thermoplastic fiber composite material as claimed in claim17, wherein the thermoplastic molding compound A consists of copolymersselected from the group consisting of styrene-acrylonitrile copolymersand alpha-methylstyrene acrylonitrile copolymers that have been modifiedby the chemically reactive functionality maleic anhydride (MA).